Lubricant and lubrication therewith



Patented Dec. 1-3, 1938 mer -ii 2,139,758 LUBRICANT AND wnarcarron THEREWITH Arthur Walther Lewis, Elizabeth, N. 3., aasignor to Tide Water Associated Oil Company, Bayonne, N. .L, a corporation of Delaware No Drawing. Application December 8, 1936, Serial No. 114,788

.10 Claims. (01. 879) This inventionrelates to; lubricants intended vention is particularly concerned, contrasts with for service in the lubrication of internal comproblems of lubricant deterioration perse since bustion engines. The invention more particu-- -oils characterized by long life and good-stability larly is concerned with lubricating or motor oils may be just as corrosive as those of interior grade.

5 of mineral hydrocarbon origin which are nor- No theory in explanation of the observed corro- 5 mally corrosive toward bearing metal alloys of sive action or the prevention thereof, as herein the character of cadmium-silver, cadmium=- proposed according to the invention, is intended nickel, or copper-lead; and has, for an important to be relied upon.

objective, the inhibition or prevention of de- According to the present invention, 'it has terioration of such bearing metal in service by the now been found that the corrosive effect of 10 corrosive action of the lubricant thereon. ub c t n 0 8 p bearing surfaces o the Engine bearings comprising or surfaced with character referred to above may be avoided in cadmium-silver or like alloys now are frequently novel and effective manner by incorporating with employed in lieu of the more usual Babbitt such oils particular compounds having a retard- 15 metal bearings, in order to cope with extreme ing or inhibiting effect in respect of such corro- '15 service conditions of friction and temperature. sion. More specifically, the invention arises These conditions are the consequences of modern from the discovery that a compound comprising developments in internal combustion engines thio benzanilide efiects a very beneficial retardamakingavailable high sustained speeds and retion of the corrosive action of internal combusquiring bearings formed of metals or alloys havtion engine lubricating oils upon cadmium- 20 ing greater resistance to wear, and further charsilver, cadmium-nickel, copper-lead and like acterized by higher melting points necessary to hearing metal alloys. a prolonged life under the extreme thermal con- It is, therefore, an important object of the ditions existing during operation of the engine. present invention to inhibit or retard the corro- Temperatures at the bearing surfaces during .sive deterioration of cadmium-silver and like operation are much higher in the case of enbearing metal alloys in automotive service by 25 gines requiring these new bearings than formerly providing a lubricant thereforcomprising a rewas the circumstance with engines in which Babfined mineral hydrocarbon oil having incorpobitt metal bearings gave satisfactory service. rated therewith thio benzanilide insmall but Experience with bearings of the character or efiective proportion. Likewise, it is an object of type exemplified by cadmium-silver, cadmiumthe invention to improve, and to prepare imnickel and copper-lead alloys-has demonstrated, proved, motor oils of petroleum origin by inhowever, that their utility is greatly impaired by corporating therein thio benzanilide in corrosion an extreme susceptibility to rapid deterioration inhibiting proportions. The provision of an inby the corrosive action or effect of many availhibitor effective for such pu pose and comprising 35 able lubricating oils. Particularly has this eflect the aforementioned compound naturally is a been noted when the oils are of the character major objective. generally regarded as superior lubricants by con- Viewed in another aspect, the invention may venticnal criteria. be regarded as encompassing a novel method of 40 Little is known concerning the nature of the lubricating bearing metal surfaces, of the char- 40 corrosive action or its causes; but in general it acter of cadmium-silver, cadmium-nickel, cophas been observed that motor oils derived from per-lead or like alloys, by applying thereto a film selected crudes predominantly parafllnic in of lubricant comprising mineral hydrocarbon oil origin, as well as those oils from these or other having incorporated therewith a small but effeccrudes which have been improved by treatment tive proportion of thio benzanilide. With this with selective solvents,exhibitamarked tendency method of lubrication it has been found that toward corrosion of thebearings in question, 81- prolonged life and consequent improved service i though by other tokens the lubricant is of may beattained in the use-of these alloys as superior quality. Oxidation stability, as, indibearing metals for internal combustion engines,

cated by sludge or acid formation in conven particularly when operating conditions such as 50 tional testsindicative of the tendency toward high sustainedspeedaunder load occasion undeterioration of the oil itself in service, does not usually high bearing surface temperatures. 0rappear to have reliable correlation with the tenddinarily, the oil selected for use, in'applylng the ency of the 01%to corrode bearing surfaces. It is lubricating method of the invention to its in- 5 p l tha he hi h bearing surface-temperatended service, will be of a character generally tures existing under service conditions with the regarded as o1v superior grade and refining. new bearings maybea factor in occasioning the Thus, the invention finds particular utility in observed deleterious eflect of motor oils theremaking possible the beneficial use of such oils upon. It would appeanalso, that the problem by avoiding deleterious consequences otherwise so of bearing corrosion, with which the present inencountered when no preventive measures are 6c ing metal alloys as hereinbefore referred to.- It will be understood, however, that the invention contemplates no limitation in this respect, and that the method of lubrication herein described may be practiced in conjunction with mineral hydrocarbon lubricating oils taken as a broad class and regardless of origin.

Thio benzanilide' is a compound conforming to I the structural formula Solubility in mineral hydrocarbon oil of motor lubricating 011 character is limited, but the pro-.

portion necessary to accomplish the objects of the present invention is well within the limits of solubility. It suflices, therefore, simply to dissolve thio benzanllide (if desired with moderate application of heat to facilltate solution) in --motor oil intended for service-in internal combustion engines in order to'prepare for the lubrication thereof according to the invention. Prosilver and like alloys.

portions as low as 0.2% by weight of. the com pound dissolved in motor oil are shown by the illustrative data hereinafter presented to be. markedly inhibitlve of the corrosion. normallyattending the use of many lubricating oils with bearing metals of the type comprising'cadmlum- The stated percentage'is not intended as a limitation upon the contemplated scope and practice of the invention, as

obviously the inhibitor may be, and is intended to be. employed in any corrosion inhibiting proportion.

Actual operation of an internal combustion engine lubricated according to the invention was used to demonstrate the efllcacy of thio hen-- zanilide as an inhibitor of bearing corrosion. The tests were run in an eight cylinder automobile engine equipped with connecting-rod bearings of the newer type exemplified by the alloys mentioned abovefyand operated under. I carefully controlled conditions duplicated'in successive runs with and without inhibitor present in carefully the lubricating oil. New bearings weighed were used for each run, and each set comprised alternate cadmium-silver and copperlead bearings respectively. Operating conditions included an engine speed of 2850 R. P. K. under a load of brake hbrsepower and arunning period of 15 hours, this being the equivalent of I68 travel at. a speed of 51.2 miles per hour. Crank.-

case oil temperature was maintained at 300 1''. 1

and water temperature at 200. I". The-oil conse- (slightly was subjected to lubricating service far more severe than that normally to be encoimtered'.

in ordinary automotive use. At thejend of each 'runthebearingswereremovedmd "thelossjinweight livinsva of cause'dbythelubricantx The test methodducribed-abo e out in the familiar'fflnderwdbd corrosion apparatus.

"taken against the corrosive deterioration of bear- Saybolt viscosity 210 F. of 54 seconds and flash point of 425 F... gave the following results:

Milligrams loss in weight per bearing Inhibitor v Cd-Ag I Cu-Pb Nnnn I 3, 782 467 0.2 percent thiobonzaullida 267 86 The foregoing results obtained in exploratory practice of the invention under service conditions of accentuated severity clearly evidence the operative significance of thiobenzanilide as a valuable addition to motor oils intended for service in the lubrication of engines equipped with cadmium-silver andlike alloy bearings. Inspecfl tion of the comparative data presented in;tl 1e3 above table Shows a substantially complete supj'i pression of corrosion when the, inhibitor is used in proportions of 0.2%. However, for many cir; cumstances of normal automotiveuse it is likely that smaller percentage of inhibitor will sufllce since operating conditions ordinarily encountered are not as stringent as those of the test runs herein.

. The tendency of motor oils to corrode bearings of the character in question likewise may be determined by another test which affords a ready method of obtaining a comparative evaluation of motor oils in the laboratory. In this test method a group ofbearings, ordinarily including at least one each of several of the newer bearing metal alloys (viz: cadmium-silver, cadmiumnickel and copper-lead) is supported in a chambet in which air may circulate and the beari surfaces are exposedfor a period of 22 hours to a stream of oil sprayed under pressure continuously upon the corrodible area. The oil is maintained at a temperature of 335 F. to 350 F. and the spray is so directed as to'dlsperse the oil over the surfaces of the bearings. Means are provided for re-circulating the sprayed oil so that a given quantity is used for a given test, thus simulating service conditions in an engine. The measure of corrosion is taken as the loss in weight of the bearing per unit' ofexposed corrodible surface.

. Results. obtainedutilizing' the foregoing test for comparative evaluation of motor oils with and without thiobenzanilide provide further'specific illustration ofthe value, and inhibiting effectiveness of this-'comp'mmd. The oil used was the same as that hereinbefore described in connection with the reported engine tests, the inhibitor added in proportion of 0.2% by weight, and cadmium-silver, cadmium-nickel, and copper-lead bearings all were present during each run. Comparative losses in weight per square decimeter.

due to corrosion wereas follows for the respective lubrication of bearings of the type described in accordance with the invention.

I claim:

1. The method of lubrrating bearings having substantially the corrosion susceptibility characterizing cadmium-silver, cadmium-nickel and copper-lead, alloys, which consists in applying to the bearing surfaces lubricant comprising mineral hydrocarbon oil of a character normally tendingto corrode said bearing surfaces and having incorporated therein thio benzanilide in proportion effective to inhibit corrosion of said bearing surfaces during the lubrication thereof.

2. The method of claim 1, further characterized in that the added thio benzanilide is incorporated with the lubricant in proportions of the order of 0.2% by weight.

3. The method of lubricating bearing surfaces in internal combustion engines, which bearing surfaces comprise an alloy having substantially the corrosion susceptibility characterizing cadmium-silver, cadmium-nickel, and copper-lead alloys, which consists in applying to said bearing surfaces lubricant comprising mineral hydrocarbon oil of a character normally tending to cor-. rode said bearing surfaces and having incorporated therein corrosion inhibiting proportions of thio benzanilide.

4. The method of lubricating bearing surfaces in internal combustion engines, which bearing surfaces comprise an alloy having substantially the corrosion susceptibility characterizing cadmium-silver, cadmium-nickel, and copper-lead alloys, which consists in applying to said bearing surfaces lubricant comprising mineral hydrocarbon oil of a character normally tending to corrode said bearing surfaces and having incorporated therein 0.2%

5. In the lubrication of bearing surfaces, one of which is formed of an alloy having substantially the corrosion susceptibility characterizing cadmium-silver, cadmiumnickel, and copperlead alloys, with mineral hydrocarbon oil normally tending to cause substantial and rapid corrosion thereof, the method of inhibiting such corrosion which comprises incorporating with said oil corrosion inhibiting proportions of thio benzanilide.

6. In the lubrication of bearing surfaces, one

of which is formed of an alloy having substanby weight of thio benzanilide.

tialiy the corrosion susceptibility characterizing cadmium-silver, cadmium-nickel, and copperlead alloys, with mineral hydrocarbon oil normally tending to cause substantial and rapid corrosion thereof, the method of inhibiting such corrosion which comprises incorporating with said oil thio benzanilide in proportions of about 0.2% by weight.

'7. Mineral oil composition, comprising a hydrocarbon lubricating oil of motor oil character normally tending to corrode the type of bearing metal having substantially the corrosion susceptibility characterizing cadmium-silver, cadmium-nickel and copper-lead alloys when continuously applied to the surface thereof for an extended period of time at an oil temperature of.335 F., and. thio benzanilide incorporated with said oil in proportions of about 0.2% by 7 weight.

9. A lubricant for the lubrication of internal combustion engines operating at high sustained speeds and employing bearings presenting hearing surfaces of an alloy selected from the class of cadmium-silver, cadmium-nickel, and copperlead alloys, which comprises a well-refined mineral lubricating oil of the character. normally effective to cause substantial corrosion of such bearing surfaces, and added thio benzanilide incorporated with said oil in corrosion inhibiting proportions.

l0. Mineral oil composition, comprising a hydrocarbon lubricating oil of a character normally tending to corrode the type of bearing metal having substantially the corrosion susceptibility characterizing cadmium-silver, cadmium-nickel and copper-lead alloys when continuously applied to the surface thereof under service conditions, and thio benzanilide incorporated with said oil in corrosion inhibiting proportions.

AR'I'HUR WALTHER LEWIS. 

